<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
</html>
<script>
    var a, b,c;
    a=10,b=15,c=20;
    var max=a;
    max=max>b?max:b;
    max=max>c?max:c;
    alert(max);
</script>